Extended Range Weather Pattern Discussion

Extended Range Weather Pattern Discussion

Updated: September 15, 2026

North and Central Texas Long Term Trends

The general weather pattern for the rest of September across North and Central Texas will most likely continue to feature above normal temperatures and below normal precipitation. While these departures from normal are indicative of El Niño this time of year, the positive North Atlantic Oscillation (NAO) and negative Pacific-North American Pattern (PNA) phases also promote warm and dry conditions in our area potentially being part of the reason this month has been so particularly hot. Furthermore, the current positive phase of the Arctic Oscillation (AO) has resulted in a de-amplified polar jet stream keeping disturbances (and their associated early shots of cool fall air) to the north.

While this near term outlook appears bleak, signs of a pattern change are expected by the start of October. First, the AO will return to near neutral or a slightly negative phase by the end of the month. This will allow for more amplified waves in the polar jet stream and help storm systems push further south. During this same time, medium range guidance suggests that the NAO will also return to a near neutral phase which would weaken the bias towards above normal temperatures across the region. With the PNA expected to remain at least weakly negative and the continued very strong El Niño, the overall pattern for the first half of October should still favor above normal temperatures. However, odds throughout the month will increasingly favor near normal precipitation as storm systems begin to move through the southern Great Plains once again. If a more active pattern can take hold during the month of October, below normal temperatures are within the realm of possibility for the second half of the month.

November onward, long term guidance continues to depict a much different weather pattern than what is currently in place. Primarily driven by El Niño, the late fall and winter months will likely see above normal precipitation and near to slightly below normal temperatures. Of course the other planetary scale oscillations can negate or even temporarily reverse these effects. Nonetheless, the strength of the El Niño this winter will allow typical ENSO teleconnections to become more prominent and resistant to other aspects of the global circulation.

ENSO (El Niño Southern Oscillation)

El Niño continues across the Equatorial Pacific with increasing warm sea surface temperature (SST) anomalies off the South American coast. While there has been some expansion of below average temperatures from the West Pacific, anomalies in Niño regions 1+2, 3, and 3.4 continue to climb (approaching 4C in Niño 1+2). 

Despite the strength of this El Niño event with very strong anomalies all but certain this fall and winter, the most recent CPC ENSO strength probabilities suggest a quick reversal in Pacific SST anomalies by Spring 2027. 

Even in strong El Niño years, temperature anomalies don’t show a strong correlation to the ENSO phase in North and Central Texas until the fall months. The September-October-November (SON) and October-November-December (OND) 3-month periods will have a slight preference (50-60% of El Niño events) to be 1-2°F cooler than average. The signal for below normal temperatures becomes stronger once we enter the winter months, with the November-December-January (NDJ) 3-month period exhibiting a more robust chance (70-80% of El Niño events) of being 1-3°F cooler than average.  

The current and forecast ENSO phase will continue to strongly favor below normal precipitation through sometime in October. By late fall and early winter, strong El Niño will have a slight preference for above normal precipitation. The occurrence of this has only been observed in roughly half of all El Niño events since 1950, which suggests that true precipitation anomalies will be more influenced by other global scale oscillations.  

MJO (Madden-Julian Oscillation)

With El Niño in full force, the Madden-Julian Oscillation (MJO) signal is muted given the dominance of ENSO teleconnections across the Pacific Basin. Despite a slight preference amongst guidance to shift the MJO into a weak Phase2/Phase3, this signal will likely continue to be muted resulting in no impact to the weather pattern here in North and Central Texas. 

NAO (North Atlantic Oscillation)

The NAO is currently in a positive phase with the NAO index around 1. Positive NAO favors above normal temperatures across the eastern CONUS and is likely a contributing factor to the prolonged September heat the region is experiencing. The general signal amongst ensemble guidance is to return to a more neutral NAO by the end of the month. Barring the other global oscillations at play, the more neutral NAO will promote closer to average temperatures by the start of October. There is not a strong signal in precipitation anomalies in North/Central Texas during the Fall for weakly positive NAO events.

PNA (Pacific-North American Pattern)

The PNA is currently weakly negative and ensemble guidance suggests it will continue to be so until around the end of the month. Negative PNA this time of year promotes troughing over the western CONUS (particularly the Pacific NW) with ridging over the southern and southeastern US. This pattern will generally favor above normal temperatures and slightly below normal precipitation in our area (the stronger correlation; however, is with temperature anomalies).

AO (Arctic Oscillation)

As we approach the cool season here in the Northern Hemisphere, the Arctic Oscillation will increasingly become important in modulating weather patterns across North and Central Texas. Currently, the AO is in a positive phase which is characterized by low pressure at high latitudes, high pressure at low latitudes, and a relatively de-amplified polar jet stream. As such, the AO will generally promote high pressure (above normal temperatures and below normal precipitation) across the region through the end of the month when it’s expected to return to near neutral. Some ensemble members (30-40%) suggest a switch to slightly negative AO by the last week of September. Should this happen, the upper-level pattern may be amplified enough to allow a cold front or two to make it far enough south to bring a couple days of scattered showers/storms and closer to normal temperatures.